1. Field of the Invention
This application relates to staplers or staple driving devices capable of effecting an outward clinch of the staple within the workpiece as it is driven and more particular to such devices capable of being adjustable to selectively effect any amount of leg deflection within a range of leg deflections and/or to selectively effect no significant deflection or a selective amount of outward leg deflection.
2. Description of Related Art
Staple driving devices of the type herein contemplated are known in the prior art. An essential of all devices of this type, whether adjustable or not, is the provision of a movable staple leg diverting member or anvil which is normally mounted for movement into and out of the drive track. An example of a non-adjustable outward clinching mechanism is disclosed in U.S. Pat. No. 3,807,619, the disclosure of which is hereby incorporated by reference into the present specification. The anvil includes outward clinching surfaces disposed in a position to be engaged by the legs of the staple during the drive stroke of the staple by the staple driving member. The anvil also includes anvil moving surfaces disposed in a position to be engaged by the crown of the staple during the drive stroke of the staple by the staple driving member. The engagement of the anvil moving surfaces functions to move the clinching surfaces of the anvil out of the drive track toward the end of the drive stroke so as to allow the staple crown to pass through the drive track and into the workpiece.
One adjustable stapler of the type herein contemplated which is marketed by the owners of the present application achieves adjustability through a range of outward deflections by moving the anvil through a range in the direction of extent of the drive track. See also, U.S. Pat. No. 4,013,206, the disclosure of which is hereby incorporated into the present specification. In the commercially available device, no significant leg deflection is achieved by locking the anvil out of the drive track by a pair of laterally movable set screws provided solely for that purpose. There exists a need for a stapler of the type described in which adjustability as between no significant leg deflection and an adjustable range of leg deflections is achieved by an adjusting mechanism which is simpler in construction, easier to operate and more economical to manufacture than the adjustment mechanisms provided by the prior art.